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arXiv 1207.4728astro-ph.HEastro-ph.GA
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宇宙射线自调节集体逃逸的解析解

Analytic Solution for Self-regulated Collective Escape of Cosmic Rays from their Acceleration Sites

M. A. Malkov, P. H. Diamond, R. Z. Sagdeev, F. A. Aharonian, I. V. Moskalenko

摘要:

超新星遗迹(SNRs)是银河宇宙射线(CR)的主要贡献者,无论它们以何种方式向星际介质(ISM)释放CR,都能通过扩散激波加速(DSA)维持平均CR谱。然而,CRs与附近气体云的相互作用关键取决于释放机制。我们提出了两个方面的问题,一个流行的范例的CR注入ISM,根据他们被动和各向同性扩散规定的磁波动作为测试粒子。首先,我们对待逃逸CR和阿尔芬波激发他们在平等的基础上。第二,我们采用场对准的CR逃逸源外,那里的波变得很弱。一个精确的解析自相似解的CR“云”由一个昏暗的加速器释放强烈偏离测试粒子的结果。对于足够高的场线积分CR分压$Π$,CR扩散系数$D_{NL}$与其背景ISM值$D_{ISM}$:$D_{NL}\sim D_{ISM}\exp(-Π)<< D_{ISM}$相比受到强烈抑制。当$Π>>1$时,CR足够有效地驱动阿尔芬波,以建立强烈减少泄漏的传输屏障。该解在$p=p_{br}$处有一个谱突变,其中$p_{br}$满足以下方程$D_{NL}(p_{br})\simeq z^{2}/t$。

英文摘要:

Supernova remnants (SNRs), as the major contributors to the galactic cosmic rays (CR), are believed to maintain an average CR spectrum by diffusive shock acceleration (DSA) regardless of the way they release CRs into the interstellar medium (ISM). However, the interaction of the CRs with nearby gas clouds crucially depends on the release mechanism. We call into question two aspects of a popular paradigm of the CR injection into the ISM, according to which they passively and isotropically diffuse in the prescribed magnetic fluctuations as test particles. First, we treat the escaping CR and the Alfven waves excited by them on an equal footing. Second, we adopt field aligned CR escape outside the source, where the waves become weak. An exact analytic self-similar solution for a CR "cloud" released by a dimmed accelerator strongly deviates from the test-particle result. The CR diffusion coefficient $D_{NL}$ is strongly suppressed compared to its background ISM value $D_{ISM}$: $D_{NL}\sim D_{ISM}\exp(-Π)<< D_{ISM}$ for sufficiently high field-line-integrated CR partial pressure, $Π$. When $Π>>1$, the CRs drive Alfven waves efficiently enough to build a transport barrier that strongly reduces the leakage. The solution has a spectral break at $p=p_{br}$, where $p_{br}$ satisfies the following equation $D_{NL}(p_{br})\simeq z^{2}/t$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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